The present invention generally relates to reservoir systems for delivering agents into oral cavities of patients and, more particularly, to such systems which deliver controlled amounts of the agents over a prolonged period of time.
Many acute and chronic diseases which involve saliva glands can result in persistent xerostomia, that is, "dry mouth" or abnormal dryness of the mouth due to insufficient secretions. Because saliva has many important functions in the oral cavity, xerostomia can be uncomfortable and can lead to dehabilitating conditions. In many cases the condition cannot be treated curatively by the use of mechanical or chemical stimulants because of the lack of functioning saliva glands. The condition, however, can often be treated symptomatically by the use of saliva substitutes. The saliva substitutes are typically placed in the mouth by spraying, sucking, dripping, or pouring the artificial saliva into the mouth from a container which must be carried by the patient. The problem with this self administration is that there is a short duration of relief. The short duration requires the patient to keep the container continuously at hand and to frequently stop to wet the inside of their mouth, teeth, gums, tongue, throat, and anywhere else there are mucous tissues.
Several devices have been developed to improve or simplify delivery of the artificial saliva. One such device is a complete or partial maxillary denture having a palatal reservoir for storing a quantity of artificial saliva. The artificial saliva is drawn out of the reservoir when desired and the reservoir is refilled when needed. This solution has the problem of an increased palatal thickness which can cause heightened gag response, swallowing difficulties, and/or alteration of the patients' speech, particularly those patients with low palatal vaults.
Another device is a complete or partial mandibular denture having a reservoir in each lingual flange below the posterior teeth. A saliva substitute is placed in the reservoirs and is dispensed when needed. This device has the problem of bulk and also has limited application because some patients do not and/or are unable to wear dentures. Additionally, the device does not have an adjustable control of the artificial saliva flow rate. It is noted that the device of first solution also has these same problems.
Devices have also been developed for delivering drugs or other beneficial agents into the oral cavity of a patient over a prolonged period of time such as, for example, an osmotic pump. Such devices typically have a bulk which interferes with speech and swallowing and may have edges which irritate and/or lacerate any mucus membranes in comes into contact with. Such devices however, like lozenges, typically have the problem of the natural tendency for the patient to suck or chew on the device which depletes the supply in a relatively short period of time. One solution has been to directly adhere or secure the devices to teeth or buccal tissues. Such invasive attachments can cause irritation and/or difficulty in replenishing the supply as well as difficulty stabilizing the supply in place to prevent peeling, sliding, and detachment. Additionally, such devices do not hold a sufficient quantity of the beneficial agent to meet the needs of many applications. Such as, for example, treating xerostomia which requires delivery of the artificial saliva over a prolonged period of time.
Accordingly, there is a need in the art for an improved device which delivers an agent into the oral cavity of a patient over a prolonged period of time. It is preferable that the improved device holds a suitable and controllable supply of the agent yet is not bulky enough to affect the user's speech or to be readily visible. Additionally, it is preferable that the device adequately secures the agent yet does not cause irritation and is easy for the user to securely insert and remove from their mouth. Furthermore, it is preferable that the device can be used by patients with and without dentures.